Governor



Nov, 5, 19.2%.,

G C. TAYLQR GOVERNOR Film: April 1.1,,

2 Sheets-Sheet l G.C.Taqlor INVENTOR ATTORNEY G. c. TAYLOR 1,734,453

GOVERNOR Filed April 11, 1925 2 Sheets-Sheet 2 Nov. 5, 1929.

L% n 1 a A m 2; A. G m, N n%k m.

\ ZW H w a %?ZPM a, Q OZ C ATTORNEY Patented Nov. 5, 1929 UNITED STATES PATENT OFFICE GEORGE C. TAYLOR, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOB 'I'O WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA GOVERNOR Application filed April 11, 1925. Serial No. 22,435.

efi'ect extremely close regulation of the Illachine governed.

Apparatus embodying features of my invention is illustrated in the accompanying drawings forming a part of this application in which Fig. l is a view, partly in section, showing an elastic fluid turbine having my improved governing apparatus applied thereto, and Fig. 2 is a vertical sectional view of the governing apparatus, and Fig. 3 is a sectional view of a detail of the apparatus.

Apparatus for governing prime movers, such as steam turbines and similar apparatus, as heretofore known to me, has consisted of some mechanism developing a movement in response to centrifugal force, for example, the weights of a governor or the operating piston of a variable fluid pressure operated-governor. The movement developed in response to centrifugal force is opposed by some restraining means, such as a spring having definite resistance for each position assumed by the governor weights or operating piston, as the case might be. Thus, upon a decrease in load and an lncrease in speed, the centrifugal force developed would increase, imparting a closmg movement to the admission valve of the prime mover, and limiting the supply of motive fluid thereto. To provide a limited supply of motive fluid for a continued condition of reduced load necessitates a continued position of the governing apparatus as assumed under increased speed conditions. The normal speed of the apparatus was therefore greater at reduced load than at normal load.

Upon a heavy load being imposed upon the prime mover, the governing apparatus could only'supply a sufficient quantity of motive fluid thereto to carry the load when the governor weights or operating piston had assumed a position corresponding to a reduced speed. Thus the speed of the prime mover under extra heavy load is less than the speed at normal load. A prime mover equipped with such apparatus therefore ran at a different speed for each different load imposed upon it. To overcome this difficulty, automatic speed changers have been added to the usual governing apparatus so that upon a change in load and a consequent change in speed, the speed changer would operate to again bring the prime mover to the speed desired. While the desired result has been obtained by such apparatus, it has, of a necessity, been more complicated and expensive than a simple governor.

In accordance with my invention, I provide a variable fluid pressure operated governing apparatus having an element actuated by the variable fluid pressure in opposition to the force exerted by suitable resilient means. The

resilient means is secured to a floating abutment, whereby the force exerted is practically a constant. When the variable fluid ressure is above or below this constant orce, a governing movement is efiected and an equilibrium of the parts is not permanently established until the force exerted by the variable fluid pressure again approaches the constant force exerted by the resilient means. The apparatus is further so designed that upon a change in load a prompt governing movement to supply more or less motive fluid to the prime mover is eflected, followed b a more gradual movement in order to bring it to the designed speed. In this way, objectionable hunting by the governor is obviated and the prime mover runs at the same speed whether under heavy or light load.

Referring now to the drawings for a better understanding of my invention, I show in Fig. 1 at 10 an elastic fluid turbine having an admission valve 11, controlled by my improved governing apparatus at 12. The governing apparatus 12 is operated by fluid pressure varving as a function of the speed of the turbine 10, developed by a centrifugal pump' ton 17 disposed therein. The operating piston 17 is connected to the admission valve 11 through a stem 18 so that movements thereof are transmitted directly to the admission valve. The operating piston 17 is provided with an upper stem portion 19 and a lower stem portion 21 extending through, and making approximately fluid tight fits, with upper and lower cylinder covers 22 and 23 respectively. The upper stem portion 19 extends into a supply chamber 20 which is at all times in communication with the pump 13 through the conduit 15. The upper stem portion 19 is therefore at all times subjected to the governing fluid pressure which tends to force it downwardly. The lower stem portion 21 is subjected to constant or atmospheric pressure and is connected through a suitable conduit and drain 24 so that any leakage of variable fluid pressure thereby may pass back to the fluid reservoir. The upper side of the iston 17 is also connected through a suitable drain conduit 25 so that the upper face of the iston 17 is at all times in communication with the exhaust.

The area of the piston 17 is greater than the area of the upper stem portion 19 so that when fluid under pressure is admitted to the cylinder 16 beneath the piston 17, it is forced upwardly against the pressure existent in the supply chamber 20. The piston 17 is hollow and is provided with a series of ports 26-26, leading from the interior thereof to its upper side and a series of ports 27-27 leading from the interior thereof to its lower side. The hollow of the piston 17 defines a cylinder in which is located a pilot valve 28. The pilot valve 28 is also hollow so that fluid under pressure is always present in the interior thereof. It is provided with a series of ports 29 leading from the interior to the exterior thereof and which, when in communication with ports 27 serve to supply fluid under pressure to the underside of the piston 17. The pilot valve 28 is also provided with a reduced portion 31 which, when in communication with ports 26 and 27 serves to permit fluid to pass from beneath the piston 17 to the upper side thereof and thence to the exhaust through conduit 25. Between the reduced portion 31 and the ports 29-29 is an annular shoulder 32 which, when in registry with the ports 27, covers said ports and prevents the admission to, or exhaust of fluid pressure from, the underside of piston 17, whereupon said piston is held stationary by the pressure within the supply chamber 20.

Upon downward movement of the pilot valve 28, ports 27 are uncovered and fluid beneath the operatin piston 17 passes to the exhaust by way 0 the reduced portion 31,

ports 26 and exhaust connection 25. Fluid pressure acting on the stem portion 19 of the operating piston 17 forces it downwardly until it assumes its original relative position with respect to the pilot valve 28 with the gprts 27 covered by the annular shoulder 32. lmilarly, upon upward movement of the pilot valve 28, ports 29 and 27 are in registry and the operating piston is forced upwardly by the admission of motive fluid beneath it. This upward movement continues until the pilot valve and operating piston again regain their original relative positions with the ports 27 covered by the annular shoulder 32. It may thus be seen that for every movement of the pilot valve 28 there is a compensating movement by the piston 17, and that the position of the piston 17 is at all times determined by the position of the pilot valve 28. Connecting the pilot valve 28 and the upper stem portion 19 of the piston 17 is a relatively heavy spring 33, the spring 33 being seated upon the upper stem portion 19 and having a flange 34 of the pilot valve 28 resting on its upper end. The spring 33 is designed to withstand the greater portion of the force exerted by the governing variable fluid pressure and tends to resist movements of the pilot valve 28 in a downward direction. Upon deflection of the spring 33, say upon an increase in pressure, and a downward movement of the pilot valve 28, the operating piston 17 also moves downwardly carrying the spring 33 with it so that there is no further deflection thereof during additional movements of the operating piston 17. The force exerted by the spring 33 is therefore practically a constant force for all positions of the pilot valve 28 and operating piston 17.

Connected to the pilot valve 28 is a relatively light spring 36 suitably secured to the lower end of the pilot valve 28, at 37, and having its upper end secured to a piston 38 of larger area than the pilot valve 28. The piston 38 is located within a cylinder 39 and is so arranged as to permit a restricted flow of fluid under pressure thereby. The cylinder 39 is in communication at all times with the supply chamber 20 so that the under side of the piston 38 is always subjected to the governing fluid pressure tending to elongate the spring 36 and pull the pilot valve upwardly. The piston 38, the spring 36 and the pilot valve 28 therefore constitute a differential piston subjected between its heads to the variable fluid governing pressure. The spring 36 provides a resilient connection between the two heads of the differential piston, the function of which will be more particularly vdescribed later. The lower end of the pilot valve 28 is in communication at all times with the exhaust through the conduit 24 so that it is subjegted on its underside to a constant or atmospheric pressure. It may thus be seen that if a back-pressure is imposed upon the upper side of the piston 38, equal to the pressure between said piston and the pilot valve 28, the tendency of the pilot valve 28 will be to move downwardly. If the backpressure on the upper side of the piston 38 1s sufiiciently less than the pressure within the suppl chamber 20 to balance this downward ten ency, the piston 38 and pilot valve 28 will remain stationary. If the pressure above the piston 38 is further reduced, the pressure within the supply chamber 20 will cause the piston 38 and pilot valve 28 to move upwardly.

As before pointed out, the spring 33 affords a ractically constant resistance to the variable fluid pressure acting to force the pilot valve 28 downwardl and movements of the piston 38, control ing the pilot valve 28 through the spring 36, are controlled by the back-pressure thereon. It has also been pointed out that if the back-pressure existent above the piston 38 is'suflicient to off-set the tendency of downward movement of the pilot valve 28, there is a state of equilibrium and no movement of the pilot valve 28 and accompanying movement of the operating piston 17 can occur. One of the principal features of my invention is to provide means whereby the back-pressure on the piston 38 is so regulated as to establish a state of equilibrium only when the governing pressure, which is a function of the spec is of a predetermined value. The pilot valve 28 and operating piston 17 upon a change in load, do not therefore definitely assume a permanent position until the governing pressure has attained the predetermined value and the speed, which determines the governing pressure, is the same as before the change in load occurred. The parts assuming a state of equilibrium only at a predetermined governing pressure. it follows that the force exerted by the spring 36 is a con stant force when the parts are in equilibrium, regardless of the load.

In order to control the back-pressure on the piston 38, I provide an orifice connection 41 to the upper end of the cylinder 39. Within the orifice connection 41 is a valve 42 which controls the area of said orifice connection. The valve 42 is controlled by a piston 43 located within a cylinder 44, which is connected to the supply chamber 20 through .a passage 46. Fluid under pressure from the supply chamber 20 is always existent beneath the piston 43, tending to force it upwardly. Opposing the fluid pressure acting against the under side of the piston 43 is a group of dead weights 47 sufiicient to nearly balance the force exerted by the governing fluid pressure developed by the pump 13 at the desired speed of the turbine 10. In addition to the weights 47 I provide a spring 48 of relatively very light scale and so adjusted that the valve 42 has a definite position for each pressure acting against the under side of the piston 44. The apparatus is so designed that the change in area of the opening of the valve 42 upon change in governing fluid pressure is such 38 is at a greater rate than beneath it. Such a design is shown by way of example in Fig.

3 wherein the orifice connection is made oval in shape and the opening in the valve 42 is made triangular in shape. Upon downward movements of the valve 42 the pressure drop in cylinder 39 effected thereby is at a relatively greater rate than if a straight opening were employed. On the other hand, upon upward movement of the valve 42 the size of the orifice opening reduces rapidly and the back pressure built up in cylinder 39 is at a relatively greater rate than if the orifice opening effected by the valve movement were directly proportionate to the valve movements. I

The area of the valve 42 controlled by the piston 43 is such that the back-pressure imposed upon the piston 38 is such as to establish a state of equilibrium of the parts only when the pressure developed by the pump 13 is at a predetermined value corresponding to the desired speed of the turbine 10. Should it be desired to change the speed of the machine governed and establish another pressure at which the parts are in equilibrium, additional weight may be added to the dead weights 47, or the tension of the spring 48 may be adjusted as by a nut 49. Fluid flowing past 9 the valve 42 passes through a conduit 50. The conduit 50 connects to a conduit 51 which may also be arranged to connect with the drains 24 and 25, returning the fluid to a reservoir from which it is pumped.

The operation of the apparatus is as follows: Fluid under pressure developed by the pump 13 is delivered to the supply chamber 20 through the conduit 15 and acts on the upper stem 19 of the operating piston 17, tending to force it downwardly and also acts against the pilot valve 28 tending to force it downwardly. Assume that the turbine is running under a constant load and that the annular shoulder 32 is covering the ports 27. Fluid beneath the piston 17 is prevented from escaping and the piston is in a fixed position. At the same time, the pressure is acting against the piston 38 tending to force it upwardly and the area of the orifice connection 41, controlled by the piston 4'3 is such as to impose a back-pressure upon the piston 38 suilicient to hold the piston 38 and pilot valve 28 in a state of equilibrium.

Assume now there is a decrease in load and a corresponding increase in turbine speed. Fluid pressure within the supply chamber 20 momentarily increases and overcomes the force exerted by the spring 33 and the spring 36 and forces the pilot valve 28 downwardly followed by the operating piston 17, imparting a closing movement to the admission valve 11. At the same time, the piston 43 moves upwardly, moving the valve 42, thereby decreasing the area of the orifice connection 4:1, increasing the back pressure on the piston 38 and preventing upward movement of the piston 38. The first movement of the pilot valve 28 is controlled by the scale of the spring 36, said spring elongating uppn an increase in governing pressure sufficiently to place an additional load thereon commensurate with the increase in pressure. When the pilot valve 28 is moved the amount determined by the increase in govern ng pressure, it is followed by the piston 17 in a manner already described, imparting a closing movement to the admission valve 11 and restricting the supply of motive fluid to the turbine 10. The restriction of the supply of motive fluid to the turbine tends to bring it back to its normal speed, developing normal governing pressure.

With the increase in pressure, as previously described, the back-pressure upon the piston 38 increases and it moves relatively slowly downward having an action similar to a dash-pot. So long as the governing pressure is greater than the predetermlned value at the desired speed of the turbine 10, the piston 38 continues to move slowly downward until the predetermined governing pressure is attained and the piston 17, the pilot valve 28 and the piston 38 are again in equilibrium, which position of equilibrium can only be obtained when the governing pressure is at its predetermined value.

Assuming now an increase in load with a corresponding decrease in speed, the pressure developed by the pump 13 is momentarily less than normal whereupon the pressure within the supply chamber 20 is reduced. Upon reduction in pressure within the supply chamber 20, the force exerted by the springs 33 and 36 causes the pilot valve 28 to move upwardly followed by the operating piston 17 and an opening movement of the admission valve 11, increasing the speed and the governing pressure. At the same time, the area of the orifice connection 41 is increased by the valve 42 because of downward movement of the piston 43 upon the decrease in governing pressure. As the back-pressure above the piston 38 is now reduced, it moves slowly upward, finally coming to rest as previously described' for downward movement when the governing pressure has attained its predetermined value consequent upon the increased supply of motive fluid to the turbine 10. Considering the piston 38 as held stationary in a given position, the governing means consisting of the impeller, the spring 36, the pilot valve 28, the spring 33 and the piston 17, would constitute an ordinary fluid pressure governor of a type heretofore known. Such a governing means requires a change in speedand fluid pressure to deflect the spring 36 for obtaining various positions of the pilot valve, to provide the proper valve opening for carrying the load on the turbine.

That is, upon an increase in load, the speed must decrease to effect the increased valve opening to carry the increased load, and vice versa.

The setting of such a governor is changed, as is already known, by changing the position of the spring-holding member, in the present instance, by changing the position of the piston 38, whereby the speed and fluid pressure required to obtain a given valve opening are changed. The part of the construction described above which moves the piston 38 may, therefore, be considered as a means for changing the setting of a governing means, so that upon a change in load, the setting of the governing means is changed until the same desired speed effects the valve opening necessary to carrying the load on the turbine. 1

From the foregoing, it will be apparent that I have invented an improved governing apparatus capable of effecting extremely dose regulation of a prime mover and wherein the speed of the prime mover is the same at different loads.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

lVhat I claim is:

' 1. In a governing apparatus for controlling an operated member in response to a variable fluid pressure, an element actuated in one direction by the variable fluid pressure, means responsive to the position of said element for controlling the operated member, resilient means for actuating theelement in the opposite direction, a floating abutment for the resilient means, and fluid pressure operated means for varying the position of the abutment, said variable fluid pressure being applied to said element at all times independently of the floating abutment.

2. In a governing apparatus for controlling an operated member in response to a variable fluid pressure, an element actuated in one direction by the variable fluid pressure, means responsive to the position of said element for controlling the operated member, resilient means for actuating the element in the opposite direction, a floating abutment for the resilient means, said floating abutment being subjected on one side to the governing variable fluid pressure, and means for imposing a back-pressure on the floating abutment varying with the governing variable fluid pressure.

3. In a governing apparatus for controlling an operated member in response to a variable 'fluid pressure, an element actuated in one direction by the variable fluid pressure, means responsive to the position of said element for controlling the operated member, resilient means for actuating the element in the opposite direction, a floating abutment for the resilient means, said floating abutment being subjected on one side to the governing variable fluid pressure, and means responsive to the governing variable fluid pressure for imposing a variable back-pressure upon the floating abutment, said backpressure increasing and decreasing in greater degree than the governing variable fluid pressure.

4. In a governing apparatus for controlling an operated member in response to a variable fluid pressure, an element actuated in one direction by the variable fluid pressure, means responsive to the position of said element for controlling the operated member, resilient means for actuating the element in the opposite direction, a floating abutment for the resilient means, said floating abutment being subjected on one side to the governing variable fluid ressure and permitting a restricted flow o fluid under pressure thereby, and means actuated by the governing variable fluid pressure for restricting the flow of fluid beyond said abutment whereby a varying back-pressure is imposed thereupon.

5. In combination, a prime mover having an admission valve, means for developing fluid pressure varying as a function of the speed of the prime mover, and a governing apparatus operated by the variable fluid pressure, said governing apparatus comprising a governing piston for actuating the admission valve, a pilot valve movable in response to variations in fluid pressure and controlling the governing piston, a spring connected to the pilot valve and opposing the variable fluid pressure, a piston subjected on one side to the variable fluid pressure supporting the other end of the spring, said piston permitting a restricted flow of fluid thereby, a cylinder for the piston subjected to the variable fluid pressure for imposing a back-pressure upon the piston, an orifice connection to the cylinder and means responsive to variations in the variable fluid pressure for varying the area of the orifice connection.

6. In combination, a prime mover having an admission valve, means for developing fluid pressure varying as a function of the speed of the prime mover, and a governing apparatus operated by the variable fluid pressure, said governing apparatus comprising a governing piston for actuating the admission valve, a pilot valve movable in response to variations in fluid pressure and controlling the governing piston, a spring connected to the pilot valve and opposing the variable fluid pressure, a piston subjected on one side to the variable fluid pressure supporting the other end of the spring, said piston permitting a restricted flow of fluid thereby, a cylinder :for the piston, an orifice connection to the cylinder opposite the side of the piston subjected to the variable fluid pressure for imposing a back-pressure upon the piston, 11 valve controlling the orifice connection, a second piston su jected to the variable fluid pressure for controlling the valve, and means associated with the second piston for opposing the variable fluid pressure.

7. In combination, a prime mover having an admission valve, means for develo ing fluid pressure varying as a function 0 the speed of the prime mover, and a governing apparatus operated by the variable fluid pressure, said governing apparatus comprising a governing piston for actuating the admission valve, a pilot valve movable in response to variations in fluid pressure and controlling the governing piston, a spring connected to the pilot valve and opposing the variable fluid pressure, a piston subjected on one side to the variable fluid pressure supporting the other end or" the spring, said piston permitting a restricted flow of fluid thereby, a cylinder for the piston, an orifice connection to the cylinder opposite the side of the piston sub jected to the variable fluid pressure for imposing a back-pressure upon the piston, a valve controlling the orifice connection, a second piston subjected to the variable fluid pressure for controlling the valve, and means including a spring of relatively light scale associated with the second piston for opposing the variable fluid pressure.

8. In a governing apparatus for controlling an operated member in response to a variable fluid pressure, a diflerential controlling piston subjected between its heads to the variable fluid pressure and having the outer side of its smaller head subjected to a constant pressure, means for moving the operated member in accordance with the position of the smaller head, and means responsive to the variable fluid pressure for imposing a variable back-pressure upon the outer side of the larger head.

9. In a governing apparatus for controlling an operated member in response to a variable fluid pressure, a diflerential controlling piston subjected between its heads to the variable fluid pressure and having the outer side of its smaller head subjected to a constant pressure, means for moving the operated member in accordance with the position of the smaller head, resilient means connecting the two heads, and means responsive to the variable fluid pressure for imposing a variable back- }preslsure upon the outer side of the larger 10. In a governingapparatus for a prime mover having an admission valve, the combination of means for developing fluid pressure varying with the speed of the prime mover, a housing including a cylinder, an

operating piston within the cylinder for controlling the admission valve, a piston valve subjected on one side to the variable fluid pressure and on the opposite side to a constant pressure for controlling the operating piston, a relatively heavy spring connecting the piston valve and the operating piston and o posing the variable fluid pressure, a piston cl greater area than the piston valve yieldingly connected thereto, said piston being subjected to the variable fluid pressure in a direction opposite to the pressure exerted on the piston valve, and means for imposing a back-pressure upon the piston of greater area, said back-pressure varying with the variable fluid pressure.

11. In a governing apparatus for a prime mover having an admission valve, the combination of means for developing fluid pressure varying with the speed of the prime mover, an operating piston for controlling the admission valve, a piston valve subjected on one side to the variable fluid pressure and on the opposite side to atmospheric pressure, a relatively heavy spring connected to the piston valve and opposing the variable fluid pressure, a piston of greater area than the piston valve connected thereto by a relatively light spring, said piston being subjec'ted to the variable fluid pressure in a direction opposite to the pressure exerted on the piston valve and permitting a restricted flow of fluid thereby, a cylinder for the piston of greater area, an ori ce connection to the cylinder opposite the side of the piston subjected to the variable fluid pressure for imposing a back-pressure upon said piston of greater area, a valve controlling the orifice connection, a second piston subjected to the variable fluid pressure for controlling the valve, and means including a spring of relatively light scale associated with the second piston for opposingthe variable fluid pressure.

12. In a governor for a prime mover, the combination of an element, means responsive to the position of said element for controlling the supply of motive fluid to the prime mover, a spring having one end connected to said element, a spring-holding element connected to the other end of said spring, and means for moving the spring-holding member in a direction for decreasing the supply of motive fluid when and as long as the speed of said prime mover exceeds a redetermined value aid for moving the spring-holding member in a direction for increasin said supply when and as long as said spee falls below said predetermined value.

13. In a governor for a prime mover, the combination of an element, means for moving said element in one direction as long as the speed of the prime mover exceeds a predetermined value and for moving said element in the opposite direction as long as the speed of the prime mover does not equal the predetermined value, a second element, means for moving the second element relatively to the first element in response to changes in speed of the prime mover, and means responsive to the position of the second element for controlling the supply of motive fluid to the prime mover.

14. In a governor for a prime mover, the

combination of an element, means for moving said element in one direction as long as the speed of the prime mover exceeds a predetermined value and for moving said element in the opposite direction as long as the speed of the prime mover does not equal the predetermined value, a second element, means for moving the second element relatively to the first element in response to changes in speed of the prime mover, the last-mentioned means being arranged to move said second element relatively to the first element more rapidly than the flrst-mentioned-means moves said first element, and means responsive to the position or" the second element for controlling the supply of motive fluid to the prime mover.

15. In a governor for a prime mover, the combination of an element, means for bringing said element to a position corresponding to the load on the prime mover, a second element, means for moving the second element relatively to the first element in response to changes in speed of the prime mover, and means responsive to the position of the second element for controlling the supply of motive fluid to the prime mover.

16. In a governor for a prime mover, the combination of an element, means for bringing said element to a position corresponding to the load on the prime mover, a second element, means for moving the second element relatively to the first element in response to changes in speed of the prime mover, the last-mentioned means being arranged to move the second element relatively to the first element more rapidly than the first-mentioned means moves the first element, and means responsive to the position of the second element for controlling the supply of motive fluid to the prime mover.

17. In a governing apparatus forcontrolling an operated member in response to a variable fluid pressure, an element actuated in one direction by the variable fluid pressure, means responsive to the position of said element for actuating the operated member, resilient means for actuating the element in the opposite direction, a floating abutment for the resilient means, and fluid pressure means for moving said floating abutment in one direction as long as the variable fluid pressure exceeds a predetermined value and for moving said abutment in the other direction as long as the variable fluid pressure is less than the predetermined value.

- 18. In a governing apparatus for controlling all) an operated member in response to a variable fluid ressure, an element actuated in one direction by the variable fluid pressure, means responsive to the position of said element for actuating the operated member, resihent means for actuating the element in the opposite direction, a floating abutment for the resilient means, and fluid pressure operated means for varying the position of the abutment, said last-mentioned means being arranged to move said abutment as long as the variable fluid pressure varies from a predetermined value.

19. In a governing apparatus for a prime mover, the combination of means providing fluid pressure varying as a function of the speed of the prime mover, an element responsive to said fluid pressure, resilient means for biasing said element, a floating abutment for said resilient means, means operated by said fluid pressure for varying the position of the abutment, an operating piston separate from the floating abutment, means for moving said piston in response to movement of said element, and means actuated by the operating piston for controlling the admission of motive fluid to the prime mover.

20. In a governing apparatus for a prime mover, the combination of means providingfluid pressure varying as a function of the speed of the prime mover, an element responsive to said fluid pressure, resilient means for biasing said element, a floating abutment for said resilient means, fluid pressure operated means for bringing the floating abutment to a position corresponding to the load on the prime mover, an operating piston separate from the floating abutment, means for moving said piston in response to movement of said element, and means actuated by the operating piston for controlling the admission of motive fluid to the prime mover.

21. In a governing apparatus for a prime mover, the combination of means providing a fluid pressure varying as a function of the speed of the prime mover, a pressure-responsive element, fluid pressure means for mov ing said element as long as the speed of said prime mover departs from a predetermined value, a second element movable relatively to the first pressure responsive element in response to variations in the variable fluid pres sure, and means responsive to the position of the second element for controlling the admis sion of motive fluid to the prime mover.

22. In a governing apparatus for a prime mover, the combination of means providing a fluid pressure varying as a function of the speed of the prime mover, a pressure-responsive element, fluid pressure means for moving said element as long as the speed of said prime mover departs from a predetermined value, a second element movable relatively to the first pressure responsive element in response to variations in the variable fluid pressure, the second pressure-responsive element being more rapidly movable than the first pressure-responsive element, and means responsive to the position of the second element for controlling the admission of motive fluid to the prime mover.

23. In a governing apparatus for a prime mover, the combination of means roviding a fluid pressure varying as a function of the speed of the prime mover, a pressure responsive element, fluid pressure means for bringing said element to a position corresponding to the load on the prime mover, a second element movable relatively to the first pressureresponsive element in response to variations in the variable fluid pressure, an operating piston separate from the first element, means for moving said piston in response to movement of the second element, and means operated by the operating piston for controlling the admission of motive fluid to the prime mover.

24. In a governing apparatus for a prime mover, the combination of means providing a fluid pressure varying as a function of the speed of the prime mover, a pressure responsive element, fluid pressure means for bringing said elementto a position corresponding to the load on the prime mover, a second element movable relatively to the first pressure responsive element in response to variations in the variable fluid pressure, the second pressure responsive element being more rapidly movable than the first pressure responsive element, an operating piston separate from the first element, means for moving said piston in response to movement of the second element, and means operated by the operating piston for controlling the admission of motive fluid to the prime mover.

25. In a governor for controlling an operated member in response to a variable fluid pressure, the combination of a floating element, means for moving said element in one' direction as long as the variable fluid pressure exceeds a predetermined value and in the opposite direction as long at it does not attain a predetermined value, a second element, a spring biasing the second element relative to the first element, means for applying said variable fluid pressure to said second element in opposition to the bias of the spring thereon, and means responsive to the position of the second element for actuating the open atcd member.

26. In a speed-responsive governor for a prime mover, the combination of a movable element, means for moving said element in one direction as long as the prime mover exceeds a predetermined speed and in the opposite direction as long as it does not attain a predetermined speed, a second element, means responsive to the position of the second element for controlling the admission of fluid to said prime mover, a spring biasing the second element relative to the first element, means providing a governing force varying as a function'of the speed of the prime mover, and means for applying said governing force to the second element in opposition to the bias of said spring.

27. In a governing apparatus for a prime mover having an admission valve, the combi nation of governing means responsive to the 19 speed of the prime mover and, for a given setting thereof, providing increased opening of said admission valve upon decreased speed, and decreased opening upon increased speed,

means providing a fluid pressure varying as a function of the speed of the prime mover, and means responsive to said fluid pressure for chan ing the setting or" said governing means in valve-opening direction as long as said fluid pressure is less than a predeter go mined value and in valve-closing direction as long as the fluid pressure is above a predetermined value.

28. In a governing apparatus for a prime mover having an admission valve, the combination of means providing a fluid pressure varying as a function of the speed of the prime mover, governing means responsive to said fluid pressure and, for a given setting thereof, providing increased opening of said admission valve upon decreased fiuid pressure and decreased opening upon increased fluid pressure, and means responsive to said fluid pressure for changing the-setting of said governing means in valve-opening direction as long as said fluid pressure is less than a redetermined value and in valveclosing irection as long as the fluid pressure is above apredetermined value.

In testimony whereof, I have hereunto subscribed my name this seventh day of April,

GEORGE G. TAYLOR. 

